Published online by Cambridge University Press: 07 June 2013
For a Lie algebra $L$ over an algebraically closed field
$F$ of nonzero characteristic, every finite dimensional
$L$-module can be decomposed into a direct sum of submodules such that all composition factors of a summand have the same character. Using the concept of a character cluster, this result is generalised to fields which are not algebraically closed. Also, it is shown that if the soluble Lie algebra
$L$ is in the saturated formation
$\mathfrak{F}$ and if
$V, W$ are irreducible
$L$-modules with the same cluster and the
$p$-operation vanishes on the centre of the
$p$-envelope used, then
$V, W$ are either both
$\mathfrak{F}$-central or both
$\mathfrak{F}$-eccentric. Clusters are used to generalise the construction of induced modules.